Pre-slit Blue Screw Cap with Hole with Bonded Blue PTFE/White Silicone Septa, for 2ml 9-425 Screw Pre-Assembled Aluminum Crimp Cap with PTFE/Silicone Septa. Note: Due to the patent which PerkinElmer holds on the closures system of the Headspace vials, the caps, septa, and star springs cannot be sold separately. Vial